scholarly journals Time Series Analysis of Evaporation Duct Height over South China Sea: A Stochastic Modeling Approach

Atmosphere ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1663
Author(s):  
Fei Hong ◽  
Qi Zhang
Keyword(s):  
Time Series ◽  
South China Sea ◽  
Stochastic Modeling ◽  
South China ◽  
Arima Model ◽  
The South China Sea ◽  
The South ◽  
China Sea ◽  
Evaporation Duct ◽  
Evaporation Duct Height

The evaporation duct could significantly affect the work status of maritime microwave communication systems in the South China Sea. Therefore, the exact forecasting of the evaporation duct is vital for the normal operation of the systems. This study presents a stochastic modeling approach to predict the future trends of the evaporation duct over the South China Sea. The autoregressive integrated moving average (ARIMA) model has been used for modeling the monthly evaporation duct height estimated from the Climate Forecast System Reanalysis dataset released by the National Centers for Environment Prediction. The long-term evaporation duct height data were collected for a period of 10 years from 2008 to 2017. The analysis of correlation function reveals the existence of seasonality in the time series. Therefore, a seasonal ARIMA model with the form as ARIMA (0,0,1) × (0,1,2)12 is proposed by fitting the monthly data optimally. The fitted model is further used to forecast the evaporation duct variation for the year 2018 at 95% level of confidence, and high-accuracy results are obtained. Our study demonstrates the feasibility of the proposed stochastic modeling technique to predict the future variations of the evaporation duct over South China Sea.

scholarly journals Fading Characteristics in Evaporation Duct: Fade Margin for a Wireless Link in the South China Sea

IEEE Access ◽  
2018 ◽  
Vol 6 ◽  
pp. 11038-11045 ◽  
Author(s):  
Khurram Shabih Zaidi ◽  
Varun Jeoti ◽  
Micheal Drieberg ◽  
Azlan Awang ◽  
Asif Iqbal
Keyword(s):  
South China Sea ◽  
South China ◽  
The South China Sea ◽  
Wireless Link ◽  
The South ◽  
China Sea ◽  
Evaporation Duct

scholarly journals A new evaporation duct climatology over the South China Sea

2015 ◽  
Vol 29 (5) ◽  
pp. 764-778 ◽  
Author(s):  
Yang Shi ◽  
Kunde Yang ◽  
Yixin Yang ◽  
Yuanliang Ma
Keyword(s):  
South China Sea ◽  
South China ◽  
The South China Sea ◽  
The South ◽  
China Sea ◽  
Evaporation Duct

scholarly journals The Effect of Boreal Summer Intraseasonal Oscillation on Evaporation Duct and Electromagnetic Propagation over the South China Sea

Atmosphere ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1298
Author(s):  
Wentao Jia ◽  
Weimin Zhang ◽  
Jiahua Zhu ◽  
Jilin Sun
Keyword(s):  
South China Sea ◽  
South China ◽  
Dominant Role ◽  
Intraseasonal Oscillation ◽  
The South China Sea ◽  
Boreal Summer ◽  
The South ◽  
Boreal Summer Intraseasonal Oscillation ◽  
China Sea ◽  
Evaporation Duct

Intraseasonal oscillation of the evaporation duct, lasting 30–60 days, has been identified over the South China Sea (SCS) summer monsoon region based on multiple reanalyses and observational data. The boreal summer intraseasonal oscillation (BSISO) causes anomalies at the air–sea boundary and thus plays a dominant role in modulating the variation of the evaporation duct. The height and strength of the duct enhance/suppress during the negative/positive phase of the BSISO over the SCS. This results from the fact that active BSISO convection reduces solar radiation reaching the sea surface by increasing cumulus cloud cover, whereupon precipitation and water vapor transported by the enhanced southwest jet increase humidity over the air–sea boundary. Reduced air–sea temperatures and humidity differences lead to a weaker evaporation duct. Usually, the temporal evolution of the evaporation duct lags 2–4 days behind the BSISO, with the center of evaporation duct anomalies farther south than the BSISO. Simulated electromagnetic fields substantively influence the condition of the evaporation duct, with obvious over-the-horizon and radar blind spot effects in the typical negative phase of the BSISO, which is very different from standard atmospheric conditions.

scholarly journals Application of the PJ and NPS evaporation duct models over the South China Sea (SCS) in winter

PLoS ONE ◽  
2017 ◽  
Vol 12 (3) ◽  
pp. e0172284 ◽  
Author(s):  
Shaobo Yang ◽  
Xingfei Li ◽  
Chao Wu ◽  
Xin He ◽  
Ying Zhong
Keyword(s):  
South China Sea ◽  
South China ◽  
The South China Sea ◽  
The South ◽  
China Sea ◽  
Evaporation Duct

scholarly journals Statistical Analysis and Case Study of the Evaporation Duct over South China Sea

2021 ◽  
Author(s):  
Jou Ping Hou ◽  
Mong-Ling Chiao
Keyword(s):  
South China Sea ◽  
South China ◽  
The South China Sea ◽  
Lower Atmosphere ◽  
Propagation Path ◽  
Communication Link ◽  
Height Distribution ◽  
The South ◽  
China Sea ◽  
Evaporation Duct

<p>Atmospheric duct is a local inversion phenomenon that occurs in the lower atmosphere by the sea-air interaction. When it happens, electromagnetic waves are often affected by atmospheric refraction, resulting in deviations in the propagation path, and affects the effectiveness of communications and radar equipment. Atmospheric ducts often appear on the ocean in East Asia, especially the evaporation ducts in the low altitude. Evaporation ducts, which are caused by a rapid decrease in the refractive index of the lower atmosphere, are known to trap radio waves between the evaporation duct layer and the sea surface, and it exist over large bodies of water such as a sea or ocean, offers the possibility of long-range communication link because of a high percentage of occurrence with acceptable average duct height which allows trapping of radio wave propagation, primarily in the tropical regions of the world.</p><p>This study analyzes the evaporation duct height distribution that calculated by the WRF and the Paulus-Jeske evaporation duct model under two different weather patterns in 2017, and uses the high-resolution sounding data of the Dongsha Island, Taiping Island and R.V. Ocean Research I in the 2017 South China Sea Two-Island Monsoon experiment ( SCSTIMX ),and it was found that the results of the Paulus-Jeske evaporation duct model were lower than the results of the sounding data, indicating the Paulus-Jeske evaporation duct model is not applicable in the South China Sea atmosphere and walrus environment; in addition, after correcting the important parameters of the Paulus-Jeske evaporation duct model according to the characteristics of the South China Sea environment, the accuracy of the results can be greatly improved.</p>

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